Sanitation is a foundational principle of disease IPM. In apple scab, extensive literature demonstrates that practices such as urea application, leaf chopping, or combinations thereof can significantly reduce primary inoculum and subsequent infection risk. Sanitation concepts are similarly extended to bitter rot management, particularly the removal of overwintered fruit “mummies” from the canopy. While this widely repeated recommendation, there is limited published data showing the impact of mummy removal on bitter rot infection risk.
In 2025, this project was initiated to directly evaluate the contribution of canopy-retained fruit mummies to primary bitter rot infections in commercial orchards in Massachusetts.
Study Sites and Experimental Design
The study was conducted at four orchard sites during the 2025 growing season. Data from three sites were included in the final analysis; the fourth site was excluded due to inconsistent cropping conditions.
Site 1: Honeycrisp on M.26 with a history of significant bitter rot
Site 2: Honeycrisp on G.41 with historically low bitter rot incidence
Site 3: Cortland and Empire on M.7 with a history of severe bitter rot pressure...